Add custom middleware to functions

I would like to add custom middleware to do things like count API requests and other analytics type things. Is there a way to do this in Serverless. Ideally it would be similar to setting up a Custom Authorizer, but able to work for any function.

Before you spend too much time building metrics into your Lambda’s have a look at CloudWatch.

Lambda doesn’t really have the concept of middleware. If you need more then export a new function that implements the middleware and have it call your old function.

oldHandler = (event, context, callback) => {
  // Your original handler here

exports.newHandler = (event, context, callback) => {
  // Start tracking
  oldHandler(event, context, (err, success) => {
    // Log here
    callback(err, success);
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